Phasing Question
- Thread starter hasbeen
- Start date
bennychico11
...
what gear are you using? do you have a phase button? you could also make a cable that has it's hot and cold wires switched on one end and then re-record it back in.
Light
New member
There is no such thing as reversing phase. Phase is a time related issue, and inverting or reversing is not a relevant concept.
You can, however, invert the polarity, which is not the same thing as phase AT ALL. The marketing guys who print up the silk screens for consoles and such don't seem to get this, but all of those "Phase" buttons on all that gear out there are actually polarity buttons.
If your gear is balanced, it is very easy to make a polarity inverting adaptor (in fact, I would bet you could buy them if you do not have the soldering skills). You just need to make a barrel adaptor or a cable with the hot and neutral inverted on one end. If it is an XLR connector, then you reverse pins one and two. If it is a TRS cable, you reverse the tip and the sleeve.
Just remember; you are not, and can not, invert phase. You are inverting polarity. This may or may not help with phase issues, but it will never eliminate them.
THIS THREAD should clear up a little bit of what I am talking about.
Light
"Cowards can never be moral."
M.K. Gandhi
You can, however, invert the polarity, which is not the same thing as phase AT ALL. The marketing guys who print up the silk screens for consoles and such don't seem to get this, but all of those "Phase" buttons on all that gear out there are actually polarity buttons.
If your gear is balanced, it is very easy to make a polarity inverting adaptor (in fact, I would bet you could buy them if you do not have the soldering skills). You just need to make a barrel adaptor or a cable with the hot and neutral inverted on one end. If it is an XLR connector, then you reverse pins one and two. If it is a TRS cable, you reverse the tip and the sleeve.
Just remember; you are not, and can not, invert phase. You are inverting polarity. This may or may not help with phase issues, but it will never eliminate them.
THIS THREAD should clear up a little bit of what I am talking about.
Light
"Cowards can never be moral."
M.K. Gandhi
hasbeen
New member
Thanks for the link, very informative.
So, just so I have this straight...
On a preamp (Vintage Langevin racked, in this case) that has a switch marked phase, it is really just a polarity switch?
A signal that may have been recorded "out of phase" do to close micing with a mic pair, may be able to be corrected after the fact by simply reversing the polarity of the recorded signal?
Thanks again!
So, just so I have this straight...
On a preamp (Vintage Langevin racked, in this case) that has a switch marked phase, it is really just a polarity switch?
A signal that may have been recorded "out of phase" do to close micing with a mic pair, may be able to be corrected after the fact by simply reversing the polarity of the recorded signal?
Thanks again!
bennychico11
...
Light said:
sorry about my stating phase earlier...you're right. my bad
Light
New member
Let's put it this way:
Phase - an incredibly complex array of issues involving the time discrepancies of two signals containing information which is nearly identical.
Polarity - The direction of the first movement of an electrical signal.
So, if you have an electrical signal (and that is all audio is) which makes its first movement as a positive voltage, than when you invert the polarity of the signal it will make its first movement as a negative signal. It becomes a mirror image of itself.
Phase is to do with time. If you have two mics picking up the same glockenspiel, then the sound will arrive at the two mics at slightly different times. Now, if that glockenspiel put out sine waves, and the mics were exactly as far apart as one half the frequency of the sine wave, then it would look exactly like reversed polarity, after the first half of a wave. In this, completely theoretical and totally non-existent example, pushing the polarity switch would completely fix the problem. But in the REAL world, it doesn't work that way. The glockenspiel does not put out sine waves. It puts out complex waves. Complex waves have many different frequencies embedded in them (look up the harmonic series sometime) and each frequency has a different wave length. Your mics can, of course, only be one distance apart. There for, while the polarity switch will eliminate the phase issues at one frequency, it will exacerbate them at almost every other frequency.
So obviously, the polarity switch is kind of like using a two shot Derringer against an Abrams M1-A1 tank. It doesn’t work too well. None the less, it can make a difference, and is sometimes enough. Make some adaptors, and try them out. Just don't confuse them, because while polarity affects phase relationships, they are not the same thing at all.
Light
"Cowards can never be moral."
M.K. Gandhi
Phase - an incredibly complex array of issues involving the time discrepancies of two signals containing information which is nearly identical.
Polarity - The direction of the first movement of an electrical signal.
So, if you have an electrical signal (and that is all audio is) which makes its first movement as a positive voltage, than when you invert the polarity of the signal it will make its first movement as a negative signal. It becomes a mirror image of itself.
Phase is to do with time. If you have two mics picking up the same glockenspiel, then the sound will arrive at the two mics at slightly different times. Now, if that glockenspiel put out sine waves, and the mics were exactly as far apart as one half the frequency of the sine wave, then it would look exactly like reversed polarity, after the first half of a wave. In this, completely theoretical and totally non-existent example, pushing the polarity switch would completely fix the problem. But in the REAL world, it doesn't work that way. The glockenspiel does not put out sine waves. It puts out complex waves. Complex waves have many different frequencies embedded in them (look up the harmonic series sometime) and each frequency has a different wave length. Your mics can, of course, only be one distance apart. There for, while the polarity switch will eliminate the phase issues at one frequency, it will exacerbate them at almost every other frequency.
So obviously, the polarity switch is kind of like using a two shot Derringer against an Abrams M1-A1 tank. It doesn’t work too well. None the less, it can make a difference, and is sometimes enough. Make some adaptors, and try them out. Just don't confuse them, because while polarity affects phase relationships, they are not the same thing at all.
Light
"Cowards can never be moral."
M.K. Gandhi